I think your last two points make up most of the drivers. Particularly now many people are in an un-breakable relationship with their smartphones. I know many

I think your last two points make up most of the drivers. Particularly now many people are in an un-breakable relationship with their smartphones. I know many people that simply don't want to entertain the "hassle" of a relationship. It's an inconvenience for them to think about somebody else other than their own immediate needs and wants.